Method and apparatus for synchronously melting and preparing alloy

ABSTRACT

An apparatus for synchronously melting and preparing alloy, the alloy to be added is made into wire in advance, and the wire feeding speed required for the preparation of the alloy with a specific composition is calculated according to the flow rate of raw molten aluminum in the launder. In the continuous ingot casting process, the wire is continuously and stably fed into the launder of the raw molten aluminum at the wire feeding speed, and the alloy preparation is formed in real time, which is able to avoid specific gravity segregation caused by the long-term standing of melt, and realize the preparation of gradient materials while significantly improving the alloying efficiency. The present disclosure also relates to a method for synchronously melting and preparing alloy.

TECHNICAL FIELD

The present disclosure relates to a technology in the field of alloymanufacturing, and in particular to a method and an apparatus forsynchronously melting and preparing alloy.

BACKGROUND ART

Generally, aluminum alloys contain a variety of alloying elements, andcorresponding alloy components need to be added to the raw moltenaluminum during the preparation process. The alloy components can beadded in the form of pure metals (such as Mg, Zn, Cu and Si, amongothers) or master alloys (such as Al—Fe, Al—Ni, Al—Zr and Al—Sr, amongothers). In actual production, all the alloys are often added in theholding furnace, melted and left to stand before the casting process.The existing major problem is that due to the different densities ofdifferent types of added elements, adding alloying elements is likely tocause specific gravity segregation in a large holding furnace. Forinstance, Cu and Zn, which are elements with higher density, concentrateat the lower part of the holding furnace, while elements with lowerdensity such as Mg and Li concentrate at the upper part of the holdingfurnace. Strong stirring is required to keep the melt uniform.Notwithstanding, it is still highly likely that the substandard chemicalcomposition or uneven composition takes place, resulting in the alloyafter melting and preparing with unqualified quality.

SUMMARY

In light of the current problems that specific gravity segregation anduneven distribution of elements is highly likely to occur in the alloyafter melting and preparing in the large holding furnace, the presentdisclosure proposes a method and an apparatus for synchronously meltingand preparing alloy, which is able to avoid specific gravity segregationcaused by the long-term standing of melt, and thus realize thepreparation of gradient materials while significantly improving thealloying efficiency.

The present disclosure is realized through the following technicalsolutions.

The present disclosure relates to a method for synchronously melting andpreparing alloy. The alloy to be added is made into wire in advance, andthe wire feeding speed required for the preparation of the alloy with aspecific composition is calculated according to the flow rate of rawmolten aluminum in the launder. In the continuous ingot casting process,the wire is continuously and stably fed into the launder of the rawmolten aluminum at the wire feeding speed, thereby real-time forming thealloy preparation.

The wire is alloy wire or pure metal wire.

As for the wire feeding speed, the wire feeding speed V_(wire) isdetermined according to the flow rate V₁ of the molten aluminum in thelaunder, i.e., V_(wire)=kV₁, where k is a fixed constant.

The real-time forming refers to: in order to make the wire quickly bedissolved into the raw molten aluminum, the method of high-frequencyinstantaneous heating is applied to melt the alloy with high meltingpoint while the wire is being fed, so that the melted alloy can beguided and diverted into the molten aluminum to enable rapid mixing torealize the required concentration of the alloying elements.

The alloy with high melting point refers to an alloy with a meltingpoint higher than that of pure aluminum, such as Al—Mn, Al—Fe, Al—Cr andthe like.

The present disclosure relates to an apparatus for realizing the abovemethod, comprising: a launder for molten aluminum and at least oneguiding tube having a wire feeding device disposed in the launder formolten aluminum, wherein the wire feeding device is disposed at theinlet end of the guiding tube and is connected with a movement controldevice, so as to adjust the feeding speed of the wire, and a temperaturecontrol device is disposed at the outlet end of the guiding tube, so asto adjust the temperature of the wire when the wire enters the launderfor molten aluminum.

The guiding tube is a hollow curved tube, with the wire arranged inside,and the bending direction of the guiding tube is the same as the flowdirection of the molten aluminum in the launder for molten aluminum.

The depth of the guiding tube inside the launder for molten aluminum isdetermined according to the depth of the launder, and is preferably ½˜⅔of the depth of the launder.

The movement control device comprises: a movement controller module, anda driver module, an execution module and a feedback sensor module, whichare connected to the movement controller module, respectively, whereinthe driver module converts the control command from the movementcontroller into a current or voltage to control electrical level, andthe feedback sensor module outputs the position of the execution moduleto the movement controller.

The temperature control device comprises: an electric temperaturetransmitter module, an electronic potentiometer module, an electriccontroller module and a silicon controlled rectifier voltage regulatormodule, wherein the temperature change is measured by a thermocouple,and converted into 0-10 mA of DC current signal, which is standardsignal of model meter, through the electric temperature transmitter;then the DC current signal is transmitted to the electronicpotentiometer for recording, and at the same time transmitted to theelectric controller, wherein the controller outputs a 0˜10 mA of DCcurrent signal and transmits the same to the silicon controlledrectifier voltage regulator after a calculation, which is according tothe magnitude and direction of the bias and pursuant to thepredetermined control rule. Then AC voltage is adjusted to realizeautomatic control.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of the apparatus of the presentdisclosure;

where 1 wire feeding device, 2 wire, 3 ceramic guiding tube, 4 highfrequency induction coil, 5 launder, 6 movement control device, 7temperature control device, 8 molten drop, 9 raw molten aluminum.

DETAILED DESCRIPTION OF EMBODIMENTS Embodiment 1

As indicated in FIG. 1, the present embodiment relates to thesynchronously melting and preparing alloy, comprising: several sets ofguiding tube 3 having wire feeding device 1, wherein the outlet end ofeach of the guiding tubes 3 is disposed in the launder 5 and outlet endof each of the guiding tubes 3 is provided with a high frequencyinduction coil 4 connected to the temperature control device 7. The wirefeeding device 1 is connected to the movement control device 6, so as tocontrol the speed of the wire 2 entering the launder 5, and the outletend of the guiding tube 3, heated by the high frequency induction coil4, melts the wire 2 into molten drops 8 and introduces the same into theraw molten aluminum 9.

The guiding tubes 3 are immersed in the raw molten aluminum 9.

During the alloying process, the raw molten aluminum flows stably in thelaunder at the speed of v_(L) (<3 m/s); the alloy wire required to beadded, which has a diameter of d₁, d₂, d₃ (<30 mm), respectively, is fedinto the ceramic guiding tubes through the wire feeding devices at thespeed of v₁, v₂, v₃ (<5 m/s), respectively. The wire feeding speed iscorrelated with the concentration level of this element in the ingot tobe prepared, and is controlled by the movement control device. Driven bythe wire feeding device, the alloy wire moves downward in the ceramicguiding tube. The high frequency induction coils are controlled by thetemperature control device to heat the corresponding local areas up tothe temperatures of T₁, T₂, T₃ (>melting point of the alloy wire),respectively, such that the alloy wire is rapidly melted to form moltendrops, and the formed molten drops continue to enter into the raw moltenaluminum along the ceramic guiding tubes, thereby achieving the alloyingand uniform distribution along with the movement of the raw moltenaluminum.

The guiding tube 3 having the wire feeding device 1 may be determinedaccording to the number of elements to be added, and multiple sets canwork simultaneously to achieve the online alloying of multiple alloyingelements at the same time. After the alloying is completed, the alloymelt can enter the casting apparatus for casting to form an ingot.

In this embodiment, the Al—Mg—Si alloy was prepared by theabove-mentioned apparatus: the raw molten aluminum was controlled toflow stably in the launder at the speed of 0.22 m/s, and the puremagnesium wire with a diameter of 1.8 mm and the Al-20Si alloy wire witha diameter of 3.0 mm were fed into the ceramic guiding tubes by the wirefeeding devices at speeds of 1.8 cm/s and 2.6 cm/s, respectively. Drivenby the wire feeding devices, the alloy wire moved downward in theceramic guiding tubes. The high frequency induction coils werecontrolled by the temperature control device to heat the correspondinglocal areas up to the temperatures of 700° C. and 720° C., respectively,such that the alloy wire was rapidly melted to form molten drops, andthe formed molten drops continued to enter into the raw molten aluminumalong the ceramic guiding tubes, thereby achieving the alloying anduniform distribution along with the movement of the raw molten aluminum.The alloy melt entered the casting apparatus for casting to formAl—Mg—Si alloy ingot.

Embodiment 2

In this embodiment, the Al—Zn—Mg—Cu alloy with composition gradient wasprepared by the above-mentioned apparatus: the raw molten aluminum wascontrolled to flow stably in the launder at the speed of 0.28 m/s, andpure zinc wire with a diameter of 4.0mm, pure magnesium wire with adiameter of 1.8mm, and an Al-20 Cu alloy wire with a diameter of 1.5 mmwere fed into the ceramic guiding tubes by the wire feeding devices atspeeds of 2.2 cm/s, 2.5 cm/s and 1.8 mm/s, respectively. Driven by thewire feeding devices, the alloy wire moved downward in the ceramicguiding tubes. The high frequency induction coils were controlled by thetemperature control device to heat the corresponding local areas up tothe temperatures of 460° C., 700° C. and 740° C., respectively, suchthat the alloy wire was rapidly melted to form molten drops, and theformed molten drops continued to enter into the raw molten aluminumalong the ceramic guiding tubes, thereby achieving the alloying anduniform distribution along with the movement of the raw molten aluminum.The alloy melt entered the casting apparatus for casting to formAl—Zn—Mg—Cu alloy ingot. During the preparation process, the wirefeeding speed of the pure zinc wire was uniformly reduced (wherein thewire feeding speed is reduced by 0.1 cm/s every 5 minutes), and the wirefeeding speed of the pure zinc wire was reduced to 1.0 cm/s after thecasting was completed. Tests indicate that the zinc content of theprepared alloy was 6.5% at the head of the ingot and 3% at the tail ofthe ingot, with a uniform gradient change from the head to the tail ofthe ingot.

The specific embodiments above may be partially adjusted by thoseskilled in the art in different ways without departing from theprinciple and purpose of the present disclosure. The protection scope ofthe present disclosure should be subject to the claims and is notlimited by the specific embodiments above. All implementation solutionswithin the scope thereof are bound by the present disclosure.

1. A method for synchronously melting and preparing alloy, wherein analloy to be added is made into a wire in advance, and a wire feedingspeed required for preparing an alloy with a specific composition iscalculated according to a flow rate of raw molten aluminum in a launder,wherein in a continuous ingot casting process, the wire was continuouslyand stably fed into the launder of the raw molten aluminum at the wirefeeding speed, thereby real-time forming an alloy preparation.
 2. Themethod for synchronously melting and preparing alloy melting accordingto claim 1, wherein the wire is an alloy wire or a pure metal wire; andan alloy with a high melting point refers to an alloy with a meltingpoint higher than that of pure aluminum.
 3. The method for synchronouslymelting and preparing alloy according to claim 1, wherein an alloy witha high melting point refers to Al—Mn, Al—Fe and Al—Cr.
 4. The method forsynchronously melting and preparing alloy according to claim 1, whereinthe wire feeding speed Vwire is determined according to a flow rate V1of the raw molten aluminum in the launder, wherein Vwire=kV1, where k isa fixed constant.
 5. The method for synchronously melting and preparingalloy according to claim 1, wherein the real-time forming refers to: inorder to make the wire quickly be dissolved into the raw moltenaluminum, a method of high-frequency instantaneous heating is applied tomelt an alloy with a high melting point while the wire is being fed, sothat a melted alloy is able to be guided and diverted into the rawmolten aluminum, so as to enable rapid mixing to realize a requiredconcentration of alloying elements.
 6. An apparatus for realizing themethod according to claim 1, comprising: a launder for molten aluminumand at least one guiding tube, which has a wire feeding device and isdisposed in the launder for molten aluminum, wherein the wire feedingdevice is disposed at an inlet end of the at least one guiding tube andis connected with a movement control device, so as to adjust a feedingspeed of the wire, and a temperature control device is disposed at anoutlet end of the at least one guiding tube, so as to adjust atemperature of the wire when the wire enters the launder for moltenaluminum; and the at least one guiding tube is a hollow curved tube,with the wire arranged inside, and a bending direction of the at leastone guiding tube is the same as a flow direction of the molten aluminumin the launder for molten aluminum.
 7. The apparatus according to claim6, wherein a depth of the at least one guiding tube located inside thelaunder for molten aluminum is ½˜⅔ of a depth of the launder.
 8. Theapparatus according to claim 6, wherein the temperature control devicecomprises an electric temperature transmitter module, an electronicpotentiometer module, an electric controller module and a siliconcontrolled rectifier voltage regulator module, wherein a temperaturechange is measured by a thermocouple, and converted into 0˜10 mA of a DCcurrent signal, which is a standard signal of a model meter, through anelectric temperature transmitter, and the DC current signal istransmitted to an electronic potentiometer and an electric controller,respectively, wherein the electric controller outputs 0˜10 mA of the DCcurrent signal based on a calculation pursuant to a predeterminedcontrol rule, according to a magnitude and direction of a bias, andtransmits the DC current signal to a silicon controlled rectifiervoltage regulator, thereby adjusting an AC voltage to realize anautomatic control.
 9. The method for synchronously melting and preparingalloy according to claim 2, wherein an alloy with a high melting pointrefers to Al—Mn, Al—Fe and Al—Cr.
 10. The apparatus according to claim6, wherein the wire is an alloy wire or a pure metal wire; and an alloywith a high melting point refers to an alloy with a melting point higherthan that of pure aluminum.
 11. The apparatus according to claim 6,wherein an alloy with a high melting point refers to Al—Mn, Al—Fe andAl—Cr.
 12. The apparatus according to claim 6, wherein the wire feedingspeed Vwire is determined according to a flow rate V1 of the raw moltenaluminum in the launder, wherein Vwire=kV1, where k is a fixed constant.13. The apparatus according to claim 6, wherein the real-time formingrefers to: in order to make the wire quickly be dissolved into the rawmolten aluminum, a method of high-frequency instantaneous heating isapplied to melt an alloy with a high melting point while the wire isbeing fed, so that a melted alloy is able to be guided and diverted intothe raw molten aluminum, so as to enable rapid mixing to realize arequired concentration of alloying elements.